Along with evolvement of a network from the IPv4 (Internet Protocol version 4) to the IPv6, the Internet Engineering Task Force (IETF) has established the Mobile Internet Protocol (MIP) in order to support a mobility IPv6 access of a terminal. The MIPv6 relates to three entities, i.e., a Mobile Node (MN), a Home Agent (HA) and a Correspondent Node (CN). When the MN is located in the home network, the MN communicates with the CN by using a Home of Address (HoA). When the MN moves to a foreign network, the MN has the HoA in the home network unchanged and is also provided with a temporary IP address allocated in the foreign network, i.e., a Care of Address (CoA). The MN registers with the HA in a Binding Update (BU) process and notifies the HA of a mapping relationship between the HoA and the CoA, and the HA maintains a binding list between the HoA and the CoA. After the HA accepts registration of the MN, data packet transmitted from the CN to the MN is encapsulated by the HA without changing an inner-layer address of an encapsulated data packet, that is, the inner-layer source address is the address of the CN and the inner-layer destination address is the HoA, and the outer-layer source address is the address of the HA and the outer-layer destination address is the CoA, and the HA forwards the encapsulated data packet to the MN through a tunnel; and the MN transmits a data packet to the CN with the outer-layer source address being the CoA and the outer-layer destination address being the address of the HA, and the inner-layer source address being the HoA and the inner-layer destination address being the address of the CN, and the HA de-encapsulates the data packet upon reception of the data packet transmitted through a reverse tunnel from the MN and forwards the de-encapsulated data packet to the CN. The HA forwards the data packet of the MN in a communication mode referred to as a bidirectional tunnel model.
The Proxy Mobile IPv6 (PMIPv6) refers to an extension to the MIPv6 and differs from the MIPv6 in that a Mobile Access Gateway (MAG) emulates the home network by notifying the hosted MN of the prefix of the home network so that the MN believes that it is located in the home network all the time; and the MAG registers with a Local Mobility Anchor (LMA) capable of functioning as the home agent, on behalf of the MN in a Proxy Binding Update (PBU) process, and finally a bidirectional tunnel between the MAG and the LMA is established for transmitting a data packet of the MN with the interface address of the MAG being the CoA.
In an existing PMIPv6-based data transmission flow as illustrated in FIG. 1, the MN transmits a Router Solicitation message to the hosting MAG after accessing the PMIPv6 domain in an attachment process; the MAG registers with the LMA on behalf of the MN by transmitting a Proxy Binding Update (PBU) message to the LMA and notifies the LMA of a mapping relationship between the interface address of the MAG and address information of the MN; the LMA accepts registration of the MAG on behalf of the MN, stores in a Binding Cache Entry (BCE) the mapping relationship between the address information of the MN and the interface address of the MAG and returns a Proxy Binding Ack (PBA) message to the MAG; the MAG returns a Router Advertisement message to the MN upon reception of the PBA message, which indicates successful establishment of a bidirectional tunnel between the MAG and the LMA; and subsequently a data packet of the MN is transmitted over the bidirectional tunnel established between the MAG and the LMA.
The inventors have identified that in the existing 3GPP Long-Term Evolvement (LTE) system, a separate GTP-U tunnel may be created for each PDP Context/EPS Bearer of the terminal and a Service Data Flow (SDF) may be bound to the GTP-U tunnel corresponding to the PDP Context/EPS Bearer to thereby enable distinguishing and charging control based upon the service data flow. In a MIPv6-based multi-connection (Monami) scenario, the HoA of the MN is allowed to be bound with a plurality of CoAs, and then one or more flows are bounded onto one of the CoAs to thereby forward the different flows onto different network interfaces. However, data packets of the MN cannot be distinguished and controlled based on the service flow in the existing PMIPv6-based data transmission solution.